fix: extract senderId from event.prompt instead of ctx in hooks

Root cause: PluginHookAgentContext in before_model_resolve only has
agentId, sessionKey, sessionId, workspaceDir, messageProvider.
senderId, channelId, input are NOT available in this hook phase.

The plugin was reading ctx.senderId (undefined) -> inHumanList=false
for ALL Discord sessions -> shouldUseNoReply=true -> all silenced.

Fix: use event.prompt which contains the full user message including
the 'Conversation info (untrusted metadata)' JSON block, and extract
sender_id from there. Same fix applied to before_prompt_build.

plugin/index.ts

@@ -356,32 +356,47 @@ export default {
       }
     });
 
-    api.on("before_model_resolve", async (_event, ctx) => {
+    api.on("before_model_resolve", async (event, ctx) => {
       const key = ctx.sessionKey;
       if (!key) return;
 
       const live = getLivePluginConfig(api, baseConfig as WhisperGateConfig) as WhisperGateConfig & DebugConfig;
       ensurePolicyStateLoaded(api, live);
 
+      // In before_model_resolve, ctx only has: agentId, sessionKey, sessionId, workspaceDir, messageProvider.
+      // senderId/channelId/input are NOT available. Use event.prompt (user message incl. untrusted metadata).
+      const channel = (ctx.messageProvider || "").toLowerCase();
+      if (live.discordOnly !== false && channel !== "discord") return;
+
+      const prompt = ((event as Record<string, unknown>).prompt as string) || "";
+      const conv = extractUntrustedConversationInfo(prompt) || {};
+      const senderId =
+        (typeof conv.sender_id === "string" && conv.sender_id) ||
+        (typeof conv.sender === "string" && conv.sender) ||
+        undefined;
+      const channelId =
+        (typeof conv.channel_id === "string" && conv.channel_id) ||
+        (typeof (conv as Record<string, unknown>).conversation_label === "string"
+          ? undefined
+          : undefined);
+
       let rec = sessionDecision.get(key);
       if (!rec || Date.now() - rec.createdAt > DECISION_TTL_MS) {
         if (rec) sessionDecision.delete(key);
-        const c = (ctx || {}) as Record<string, unknown>;
-        const derived = deriveDecisionInputFromAgentCtx(c);
         const decision = evaluateDecision({
           config: live,
-          channel: derived.channel,
+          channel,
-          channelId: derived.channelId,
+          channelId,
           channelPolicies: policyState.channelPolicies,
-          senderId: derived.senderId,
+          senderId,
-          content: derived.content,
+          content: prompt,
         });
         rec = { decision, createdAt: Date.now() };
         sessionDecision.set(key, rec);
         pruneDecisionMap();
-        if (shouldDebugLog(live, derived.channelId ?? ctx.channelId)) {
+        if (shouldDebugLog(live, channelId)) {
           api.logger.info(
-            `whispergate: debug before_model_resolve recompute session=${key} decision=${decision.reason} ` +
+            `whispergate: debug before_model_resolve recompute session=${key} senderId=${senderId} decision=${decision.reason} ` +
               `shouldNoReply=${decision.shouldUseNoReply} shouldInject=${decision.shouldInjectEndMarkerPrompt}`,
           );
         }
@@ -399,7 +414,7 @@ export default {
       };
     });
 
-    api.on("before_prompt_build", async (_event, ctx) => {
+    api.on("before_prompt_build", async (event, ctx) => {
       const key = ctx.sessionKey;
       if (!key) return;
 
@@ -409,20 +424,31 @@ export default {
       let rec = sessionDecision.get(key);
       if (!rec || Date.now() - rec.createdAt > DECISION_TTL_MS) {
         if (rec) sessionDecision.delete(key);
-        const c = (ctx || {}) as Record<string, unknown>;
+
-        const derived = deriveDecisionInputFromAgentCtx(c);
+        // before_prompt_build has event.prompt and event.messages available.
+        const channel = (ctx.messageProvider || "").toLowerCase();
+        const prompt = ((event as Record<string, unknown>).prompt as string) || "";
+        const conv = extractUntrustedConversationInfo(prompt) || {};
+        const senderId =
+          (typeof conv.sender_id === "string" && conv.sender_id) ||
+          (typeof conv.sender === "string" && conv.sender) ||
+          undefined;
+        const channelId =
+          (typeof conv.channel_id === "string" && conv.channel_id) ||
+          undefined;
+
         const decision = evaluateDecision({
           config: live,
-          channel: derived.channel,
+          channel,
-          channelId: derived.channelId,
+          channelId,
           channelPolicies: policyState.channelPolicies,
-          senderId: derived.senderId,
+          senderId,
-          content: derived.content,
+          content: prompt,
         });
         rec = { decision, createdAt: Date.now() };
-        if (shouldDebugLog(live, derived.channelId ?? ctx.channelId)) {
+        if (shouldDebugLog(live, channelId)) {
           api.logger.info(
-            `whispergate: debug before_prompt_build recompute session=${key} decision=${decision.reason} ` +
+            `whispergate: debug before_prompt_build recompute session=${key} senderId=${senderId} decision=${decision.reason} ` +
               `shouldNoReply=${decision.shouldUseNoReply} shouldInject=${decision.shouldInjectEndMarkerPrompt}`,
           );
         }
@@ -430,7 +456,7 @@ export default {
 
       sessionDecision.delete(key);
       if (!rec.decision.shouldInjectEndMarkerPrompt) {
-        if (shouldDebugLog(live, ctx.channelId)) {
+        if (shouldDebugLog(live, undefined)) {
           api.logger.info(
             `whispergate: debug before_prompt_build session=${key} inject=false reason=${rec.decision.reason}`,
           );